title: IL-10 inhibits macrophage activation and proliferation by distinct signaling mechanisms: evidence for Stat3-dependent and -independent pathways.
abstract: Interleukin-10 (IL-10) limits inflammatory responses by inhibiting macrophage activation. In macrophages, IL-10 activates Stat1 and Stat3. We characterized IL-10 responses of the J774 mouse macrophage cell line, and of J774 cells expressing wild-type hIL-10R, mutant hIL-10R lacking two membrane-distal tyrosines involved in recruitment of Stat3 (hIL-10R-TyrFF), a truncated Stat3 (DeltaStat3) which acts as a dominant negative, or an inducibly active Stat3-gyraseB chimera (Stat3-GyrB). A neutralizing anti-mIL-10R monoclonal antibody was generated to block the function of endogenous mIL-10R. IL-10 inhibited proliferation of J774 cells and of normal bone marrow-derived macrophages, but not J774 cells expressing hIL-10RTyrFF. Dimerization of Stat3-GyrB by coumermycin mimicked the effect of IL-10, and expression of DeltaStat3 blocked the anti-proliferative activity of IL-10. For macrophage de-activation responses, hIL10R-TyrFF could not mediate inhibition of lipopolysaccharide-induced TNFalpha, IL-1beta or CD86 expression, while DeltaStat3 did not interfere detectably with these IL-10 responses. Thus signals mediating both anti-proliferative and macrophage de-activation responses to IL-10 require the two membrane-distal tyrosines of IL-10R, but Stat3 appears to function only in the anti-proliferative response.
authors.affiliation: Department of Molecular Biology, DNAX Research Institute, Palo Alto, CA 94304-1104, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: O'Farrell
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: K W
authors.initials: KW
authors.lastname: Moore
authors.forename: A L
authors.initials: AL
authors.lastname: Mui
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000302:isolation & purification / Q000502:physiology; D015703:Antigens, CD / Q000096:biosynthesis / Q000187:drug effects; D051940:B7-2 Antigen; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D005260:Female; D006131:Growth Inhibitors / Q000502:physiology*; D006801:Humans; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D016753:Interleukin-10 / Q000276:immunology / Q000502:physiology*; D008262:Macrophage Activation / Q000187:drug effects / Q000276:immunology; D008264:Macrophages / Q000166:cytology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000187:drug effects; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D017452:Receptors, IgG / Q000096:biosynthesis; D018123:Receptors, Interleukin / Q000235:genetics / Q000502:physiology; D053701:Receptors, Interleukin-10; D050796:STAT3 Transcription Factor; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D014443:Tyrosine / Q000235:genetics / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D051940:B7-2 Antigen; C497964:CD86 protein, human; C497965:Cd86 protein, mouse; D004268:DNA-Binding Proteins; D006131:Growth Inhibitors; D007375:Interleukin-1; D008562:Membrane Glycoproteins; D017452:Receptors, IgG; D018123:Receptors, Interleukin; D053701:Receptors, Interleukin-10; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C494087:Stat3 protein, mouse; D015534:Trans-Activators; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D009569:Nitric Oxide; D014443:Tyrosine